1. Field of the Invention
The present invention relates to a microwave oven and, more particularly, to a microwave oven, which has a tray mounted on the bottom of a cooking chamber for laying foods thereon to travel in a rotational motion and in linearly reciprocating motion, so that the food can be uniformly cooked.
2. Description of the Related Art
Generally, a microwave oven is an appliance to cook or heat food, using a frictional heat, which is produced between moisture molecules of the food due to repeated changes in the molecular arrangement of moisture contained in the food by an irradiation of microwaves generated from a magnetron of the microwave oven into a cooking chamber.
Such a conventional microwave oven has a body defining an outer appearance of the microwave oven. The body is provided with a rectangular parallelepiped inner case therein, thereby partitioning the interior of the body into a cooking chamber at the inside of the inner case and an electric component chamber at the outside of the inner case.
The cooking chamber has a tray mounted on the bottom of the cooking chamber, which can be rotated, with food to be cooked laid thereon, by a motor provided under the bottom of the cooking chamber. The electric component chamber is equipped with the magnetron for generating the microwaves and then irradiating them into the cooking chamber, a high-voltage transformer and a high-voltage condenser for supplying a high voltage to the magnetron, etc.
With this configuration, when the microwave oven operates, the microwaves generated by the magnetron are irradiated into the cooking chamber, thereby cooking the food rotating along with the tray.
However, since the tray of the conventional microwave oven is rotated about a fixed point at a predetermined position on the bottom of the cooking chamber, there is a limitation on uniform cooking for the food.
Accordingly, in order to solve the problems mentioned above, a microwave oven, disclosed in Korean Patent Registration No. 10-0423993 issued to the applicant of the present invention, has a tray, which can travel in a rotational motion and in a linearly reciprocating motion, so that the food laid on the tray may be uniformly cooked.
The microwave oven of Korean Patent Registration No. 10-0423993 is provided with a slot hole-shaped penetrating hole formed on the bottom of a cooking chamber; a shaft, provided at a lower portion of the tray such that the shaft is extended through the penetrating hole to the outside of the cooking chamber, and having a pinion formed on an outer surface of the shaft; and a guide member fixed to the lower portion of the cooking chamber and formed with a rack engaged with the pinion. The microwave oven also includes a first link, having a first end swingably connected to an end of the shaft and a second end, and a second link, having a first end swingably connected to the second end of the first link and a second end fixed to a rotational shaft of a motor provided at the lower portion of the cooking chamber.
With this configuration, when the second link is rotated along with the rotational shaft of the motor in one direction, the pinion is rotated along the rack in the clockwise direction or in the counterclockwise direction, and the first link is pulled into the motor side or pushed to the opposite side thereof, thereby forcing the shaft to rotate and linearly reciprocate in the penetrating hole. Accordingly, the tray rotates along with the shaft on the bottom of the cooking chamber while linearly reciprocating, and thus, the food laid on the tray can be uniformly cooked through the movement of the tray.
However, although the tray of the microwave oven, disclosed in Korean Patent Registration No. 10-0423993, can rotate and linearly reciprocate in the cooking chamber, since the tray is driven by one motor, the rotational motion and the linearly reciprocating motion of the tray are always carried out simultaneously. As a result, when the rotational motion of the tray is hindered due to a large volume of the food laid on the tray, the linearly reciprocating motion of the tray becomes impossible, and on the other hand, when cooking a great amount of food at the same time with the food laid on the bottom of the cooking chamber as well as on the tray, the linearly reciprocating motion of the tray is hindered, and the rotational motion of the tray becomes thus impossible. Accordingly, in such cases mentioned above, the food cannot be uniformly cooked in the microwave oven.